While the crowds pour into the Royal Hospital Grounds at Chelsea professional gardeners are becoming an endangered species.

Where have all the gardeners gone?

While leisure gardening is set to continue growing in popularity, qualified gardeners are a dwindling breed. Leeds Council highlights the issue in its show garden this year, and top Chelsea designers like Jinny Blom are leading a call for more skilled gardeners.

"Without a rapid infusion of committed, skilled, enthusiastic, well-paid and appreciated gardeners, the whole industry of garden design is in danger of imploding," she says.

Matthew Wilson, curator of RHS Harlow Carr in Yorkshire, also has problems recruiting good gardeners. He says a lot of people are put off by the salary: highly-qualified gardeners are routinely expected to work for £6-£8 an hour.

"There's a huge amount of scientific background to horticultural training - soil science, botany, pest and disease identification," he says. "Then you come out and you go and earn the same money as someone on the checkouts at a supermarket."

Gardening also has something of an image problem among youngsters.

"Getting your hands dirty isn't sexy," says Debs Goodenough, secretary of the Professional Gardeners’ Guild. "We need a Jamie Oliver - someone to convince kids what a good profession it is."

The RHS is getting gardening back into schools with programmes such as its Schools Membership Scheme and its outreach programme, Flourish. But, says Debs, it's a slow process - and parents need convincing as much as teachers.

Leeds Council is using its show garden this year to point out the loss of another key source of good gardeners: parks department apprenticeships. Tight budgets and competitive tendering have largely ended learning on the job from more experienced gardeners.

This is one area where real progress is being made, however. Councils from Cardiff to Wakefield are re-establishing horticultural apprenticeship schemes, and a Lottery grant has helped set up an apprenticeship scheme, the Historic and Botanic Gardens Bursary Scheme to restore good gardeners to the country’s historic parks and gardens.

For the time being, though, horticulture has to rely on the growing number of career changers: people from all walks of life who leave their jobs to join a profession renowned for its job satisfaction.

"Not once have I regretted coming into this line of work," says Matthew Wilson, himself a former Sun journalist.

"And I don’t think there are many people who feel that about what they do for a living."